N. L. Prater's Petrol Refinery Data
The yield of a petroleum refining process with four covariates. The crude oil appears to come from only 10 distinct samples.
These data were originally used by Prater (1956) to build an estimation equation for the yield of the refining process of crude oil to gasoline.
N. H. Prater (1956) Estimate gasoline yields from crudes. Petroleum Refiner 35, 236--238.
This dataset is also given in D. J. Hand, F. Daly, K. McConway, D. Lunn and E. Ostrowski (eds) (1994) A Handbook of Small Data Sets. Chapman & Hall.
Venables, W. N. and Ripley, B. D. (2002) Modern Applied Statistics with S. Fourth edition. Springer.
library(nlme) Petrol <- petrol Petrol[, 2:5] <- scale(as.matrix(Petrol[, 2:5]), scale = FALSE) pet3.lme <- lme(Y ~ SG + VP + V10 + EP, random = ~ 1 | No, data = Petrol) pet3.lme <- update(pet3.lme, method = "ML") pet4.lme <- update(pet3.lme, fixed = Y ~ V10 + EP) anova(pet4.lme, pet3.lme)